Tapping the potential of vegetable Amaranth genotype to trap the root knot nematode pest

Nine genotypes of Amaranthus tricolor L. and one genotype of Amaranthus cruentus L. were evaluated for susceptibility to root knot nematode, shoot and root traits in a nematode infested plot. A significantly higher proportion of parasitism (1.0) was recorded in four of the plant genotypes. All 10 amaranth genotypes failed to develop root galls by nematodes when cultivated after a fallow crop of African marigold. Three highly susceptible genotypes and one tolerant genotype were further screened in containers filled with sterile soil. The sterile soil was inoculated with the known amount of inoculums of two populations of root knot nematode (Meloidogyne incognita Kofoid and White) in the treatments. Two populations of nematodes were native to Old Goa and Varanasi of Goa and Uttar Pradesh states of India respectively. Plants in the un-inoculated control were maintained with sterile soil only. Staining the root samples with acid fuchsin was carried to confirm the presence of egg mass and juvenile nematodes in roots. One genotype of A. tricolor, IgAtR-60 (IC0598184) recorded the high degree of nematode parasitism when intercropped in arecanut garden. The genotype also had least reduction in root and shoot traits but remained highly susceptible to inoculation with both Old Goa and Varanasi populations of M. incognita. IgAtR-60 (IC-0598184) holds promise in nematode sick plots as trap-catch intercrop after confirmatory investigations.